The Role of Regional Codes in Mitigating Residential Sector Energy Demand Sensitivity to Climate Change Scenarios in Hot–Arid Regions

Rising temperatures are intensifying residential cooling demands in hot–arid regions, with national building codes playing a pivotal role in mitigating these effects. This study evaluates the energy performance of two high-density residential buildings, Noor City in Cairo and Banan City in Riyadh, using DesignBuilder version 7.0.2.006 simulations for 2023, 2050, and 2080 under RCP 4.5 projections, followed by comparative and code-swapping analysis that assessed the role of envelope design parameters. All parameters were constant, except for those dictated by each country’s code. Results show that under future climate conditions, cooling loads in the uninsulated Noor City rise by 69% by 2080, compared to a 32% increase in Banan City. A code-swapping analysis confirmed the regulatory impact; applying the Saudi envelope to Noor City reduced annual energy use by over 40%, while using the Egyptian code in Banan City increased it by more than 50%. Solar exposure analysis further revealed that Noor City’s unshaded façades contribute to elevated thermal loads. Additionally, a 20.48 kWp rooftop photovoltaic system offsets 32:35% of annual energy consumption in both cases. While operational benefits are evident, no full life cycle cost (LCC) analysis was conducted; future studies should address economic feasibility to guide code adaptation in lower-income contexts.